# options [`options`在线教程](https://arthas.aliyun.com/doc/arthas-tutorials.html?language=cn&id=command-options) ::: tip 全局开关 ::: | 名称 | 默认值 | 描述 | | ---------------------- | ------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | unsafe | false | 是否支持对系统级别的类进行增强,打开该开关可能导致把 JVM 搞挂,请慎重选择! | | dump | false | 是否支持被增强了的类 dump 到外部文件中,如果打开开关,class 文件会被 dump 到`/${application working dir}/arthas-class-dump/`目录下,具体位置详见控制台输出 | | batch-re-transform | true | 是否支持批量对匹配到的类执行 retransform 操作 | | json-format | false | 是否支持 json 化的输出 | | disable-sub-class | false | 是否禁用子类匹配,默认在匹配目标类的时候会默认匹配到其子类,如果想精确匹配,可以关闭此开关 | | support-default-method | true | 是否支持匹配到 default method, 默认会查找 interface,匹配里面的 default method。参考 [#1105](https://github.com/alibaba/arthas/issues/1105) | | save-result | false | 是否打开执行结果存日志功能,打开之后所有命令的运行结果都将保存到`~/logs/arthas-cache/result.log`中 | | job-timeout | 1d | 异步后台任务的默认超时时间,超过这个时间,任务自动停止; 比如设置 1d, 2h, 3m, 25s,分别代表天、小时、分、秒 | | print-parent-fields | true | 是否打印在 parent class 里的 filed | | verbose | false | 是否打  印更多详细信息 | | strict | true | 是否启用 strict 模式 | ### 查看所有的 options ```bash $ options LEVEL TYPE NAME VALUE SUMMARY DESCRIPTION ------------------------------------------------------------------------------------------------------- 0 boolea unsafe false Option to support sy This option enables to proxy functionality n stem-level class of JVM classes. Due to serious security r isk a JVM crash is possibly be introduced. Do not activate it unless you are able to manage. 1 boolea dump false Option to dump the e This option enables the enhanced classes t n nhanced classes o be dumped to external file for further d e-compilation and analysis. 1 boolea batch-re-tra true Option to support ba This options enables to reTransform classe n nsform tch reTransform Clas s with batch mode. s 2 boolea json-format false Option to support JS This option enables to format object outpu n ON format of object t with JSON when -x option selected. output 1 boolea disable-sub- false Option to control in This option disable to include sub class w n class clude sub class when hen matching class. class matching 1 boolea support-defa true Option to control in This option disable to include default met n ult-method clude default method hod in interface when matching class. in interface when c lass matching 1 boolea save-result false Option to print comm This option enables to save each command's n and's result to log result to log file, which path is ${user. file home}/logs/arthas-cache/result.log. 2 String job-timeout 1d Option to job timeou This option setting job timeout,The unit c t an be d, h, m, s for day, hour, minute, se cond. 1d is one day in default 1 boolea print-parent true Option to print all This option enables print files in parent n -fields fileds in parent cla class, default value true. ss 1 boolea verbose false Option to print verb This option enables print verbose informat n ose information ion, default value false. 1 boolea strict true Option to strict mod By default, strict mode is true, not allow n e ed to set object properties. Want to set o bject properties, execute `options strict false` ``` ### 获取 option 的值 ``` $ options json-format LEVEL TYPE NAME VALUE SUMMARY DESCRIPTION -------------------------------------------------------------------------------------------- 2 bool json-format false Option to support This option enables to format object ean JSON format of obj output with JSON when -x option selec ect output ted. ``` ::: tip 默认情况下`json-format`为 false,如果希望`watch`/`tt`等命令结果以 json 格式输出,则可以设置`json-format`为 true。 ::: ### 设置指定的 option 例如,想打开执行结果存日志功能,输入如下命令即可: ``` $ options save-result true NAME BEFORE-VALUE AFTER-VALUE ---------------------------------------- save-result false true ``` ### 打开 unsafe 开关,支持 jdk package 下的类 默认情况下,`watch`/`trace`/`tt`/`trace`/`monitor`等命令不支持`java.*` package 下的类。可以设置`unsafe`为 true,则可以增强。 ```bash $ options unsafe true NAME BEFORE-VALUE AFTER-VALUE ----------------------------------- unsafe false true ``` ```bash $ watch java.lang.invoke.Invokers callSiteForm Press Q or Ctrl+C to abort. Affect(class count: 1 , method count: 1) cost in 61 ms, listenerId: 1 ``` ### 关闭 strict 模式,允许在 ognl 表达式里设置对象属性 ::: tip since 3.6.0 ::: 对于新用户,在编写 ognl 表达式时,可能会出现误用。 比如对于`Student`,判断年龄等于 18 时,可能条件表达式会误写为`target.age=18`,这个表达式实际上是把当前对象的`age`设置为 18 了。正确的写法是`target.age==18`。 为了防止出现类似上面的误用,Arthas 默认启用`strict`模式,在`ognl`表达式里,禁止更新对象的 Property 或者调用`setter`函数。 以`MathGame`为例,会出现以下的错误提示。 ``` $ watch demo.MathGame primeFactors 'target' 'target.illegalArgumentCount=1' Press Q or Ctrl+C to abort. Affect(class count: 1 , method count: 1) cost in 206 ms, listenerId: 1 watch failed, condition is: target.illegalArgumentCount=1, express is: target, By default, strict mode is true, not allowed to set object properties. Want to set object properties, execute `options strict false`, visit /Users/admin/logs/arthas/arthas.log for more details. ``` 用户如果确定要在`ognl`表达式里更新对象,可以执行`options strict false`,关闭`strict`模式。 - 更多信息参考: https://github.com/alibaba/arthas/issues/2128